In conventional practice, a manipulation such that an artificial dialysis is performed or a predetermined medicinal liquid and the like is supplied to, for example, the blood vessels of a patient is carried out with the use of an indwelling needle. The indwelling needle used in such a case includes a cannula for indwelling the needle tip within the blood vessel of the patient and a body portion connected to the basal end portion of the cannula. Then, when the tip end of this cannula is indwelled within the blood vessel, a puncturing needle for the smooth puncturing manipulation of the cannula to the blood vessel is employed. And, when the manipulation described in above is carried out, the puncturing needle is inserted into the indwelling needle to slightly project the tip end portion of the puncturing needle from the tip end portion of the cannula and, in that condition, the cannula together with the puncturing needle is punctured into the blood vessel.
Then, in the condition where the cannula is indwelled in the blood vessel, the puncturing needle is pulled out of the indwelling needle (blood vessel) and the rear end portion of the indwelling needle is connected to a tube member and the like for supplying the escaped blood, the predetermined medicinal liquid or the like to perform the artificial dialysis or supply the medicinal liquid and the like. In such an indwelling needle, there is the indwelling needle in which a valve having an opening and closing aperture is fixed within the body portion and a cylindrical connector part is moveably provided at the rear portion side of the valve within the body part, in which the connector part is pressed forwardly to insert the tip end portion of the connector part into the opening and closing aperture of the valve.
Also, by passing the tip end portion of the connector through the valve, the cannula is communicated with the connector, thereby communicating between the cannula to tube member and the like by connecting the tube member and the like to the rear end portion of the connector part via the rear end portion of the body part (For example, see Japanese Unexamined Patent Publication No. H06-509246. In this indwelling needle (catheter), one end portion of a spring is disposed at the outer peripheral surface of the rear side of the valve (self sealed diaphragm) within the body part (outer cannula hub) and the other end portion of the spring is disposed at a flange like projecting part provided to the rear end portion of the connector (shuttle) to activate the connector rearwardly.
Therefore, when the indwelling needle is indwelled in the blood vessel of the patient, the puncturing needle is inserted into the inside of the connector and then the opening and closing aperture of the valve and, in that condition, the tip end portion thereof is projected from the tip end of the indwelling needle. In this case, the connector part is located at the rear of the valve and the opening and closing aperture of the valve and the puncturing needle are tightly contacted and occluded each other. Then, when the puncturing needle is pulled out of the indwelling needle and the rear end portion of the indwelling needle is connected to the tube member and the like, the connector part is pressed by the tip end portion of the tube member and the like, whereby the tip end portion of the connector part is inserted into the opening and closing aperture of the valve. Thus, the cannula is communicated with the tube member and the like as described in above.
However, in the conventional indwelling needle described in above, since the end portion of the spring is directly contacted with the valve, the elastic force of the spring is applied to the valve all the time which causes the portion of the valve to which the elastic force of the spring is applied become a small streak portion having a small area surface resulting in that the valve may be easily deteriorated and the sealing property thereof may also readily be lowered. Further, there is a fear in this valve that the deterioration by the sterilization or by the elapse of time of a long term storage.
The invention has been made in the light of these problems and the object of the invention is to provide an indwelling needle in which the deterioration of the valve provided therewithin by the pushing pressure of the elastic member can be reduced.